Most of existing driver drowsiness preventing systems recognize a drowsy state by detecting state of a pupil through driver face recognition, or recognizes the drowsy state based on a respiration pattern according to respiration of the driver.
However, using brainwaves, a contact device for measuring the brainwaves is used. The contact device can be problematic because its attachment causes uneasiness.
Meanwhile, a method estimates an eye blink interval through a brainwave signal. When reversely estimating the eye blink using the brainwaves, error can occur according to a noise signal, and an accident prevention rate lowers as an estimation process gets longer.
When the state of the pupil is detected through the driver face recognition, an algorithm for detecting the pupil state using an image input from a camera is very complex. When the external strong light comes into the camera, error is generated. Many errors arise according to the degree of the pupil and a head location of the driver per person.
In particular, since the eye area in the face varies according to the race, error rate rises when the algorithm is applied. When the driver has the low sitting height or shakes his/her head, it gets out of the recognition range of the camera and causes error.
Also in the recognition method using the respiration, the error rate varies according to a location of a sensor which detects the respiration. When air flows from the outside or the driver opens or closes a window, it can greatly affect the sensor.
To implement an intelligent vehicle, it is quite important to obtain the state of the driver in the vehicle or a driving propensity of the driver and to send this information to other vehicle or a host system.
An accident rate caused by the drowsy driving due to fatigue or monotonousness of the driver, or the lack of oxygen inside the automobile tends to increase. Hence, to realize an intelligent automobile system for protecting the driver against the accident caused by the drowsy driving, it is necessary to develop a more effective drowsiness preventing system.